I have read a lot of stuff, and i cant find the file for my router, i downloaded the "Kernel 2.6 (experimental) for MIPSR1 Routers" "NoUSB-Std" because that's what the compatibility table told me to:

Linksys WRT160N v3 R2 Yes No NoUSB-Std (4MB flash) only

Apparently .trx is not valid(it tells me it's not a valid image), i read somewhere i could just rename it to .bin and it would work, but i dont know if that's actually right (dont want to brick my router)
So, please help me getting the right file or telling me how to fix this :)

PD: i even updated to DD-WRT because i thought that would solve this, but i still cant upgrade to a .trx
PPD: i have downloaded

tomato-K26-1.28.7483.3MIPSR2-Toastman-RT-Std . trx

which i think should be the right Toastman's mod for the router (im interested in the QoS) Thanks! ^_^

(Sorry for the double thread)
anyway, i figured out a way to deal with it, i took the risk and renamed it, and hey, it worked! :D
At first i was using a toastman's build

tomato-K26-1.28.7483.3MIPSR2-Toastman-RT-Std . trx

which i had some problems with:

It resulted a pain, i dont know what was the problem, but the router became practically unresponsive, what i had to do is set my ipaddress/gateway/subnetmask manually, just then i was able to access the tomato gui at 192.168.1.1, after that i tried configurating but it was useless, it just broke again, lol, i think i forgot to turn the manual ip off, so when i decided to restart the modem (while it had the manual ip), it ended up bringing me to a "linksys device manager" where you can pretty much recover from bricking your router by uploading a new firmware, from there i went to ddwrt and then to the tomato build listed on this page (lol, so much trouble), and it's finally working! ^_^